Life saving imaging-based percutaneous coronary intervention (PCI) catheterization procedures such as stent implantation, angioplasty, and diagnostic angiography require frequent and large injections of radiopaque contrast agents in order to visualize the blood vessels. These iodinated agents are toxic to the kidney, and exposure can lead to contrast induced nephropathy (CIN), a form of acute kidney failure, in patients with pre-existing renal insufficiency. There are 180,000 new cases of CIN every year in the United States that can lead to costly prolonged hospital stays and, at the extreme, end-stage kidney disease requiring permanent dialysis and kidney transplantation. Prophylactic procedures for preventing CIN are only marginally effective, and include curtailing interventional procedures that could otherwise benefit a patient. Using established screening criteria, about 100,000 heart disease patients currently are not eligible for PCI procedures due to concomitant chronic kidney disease, and this number is expected to increase due to a "ballooning" incidence of chronic kidney disease rates among the general population, with 25% of PCI candidates having chronic kidney disease. This incidence is expected to increase by 90% within a decade. Diabetes, a common risk factor to the use of contrast agents, currently affects approximately 20 million people in the United States, and the number is anticipated to increase by 75% by 2025. Catharos is preparing a novel contrast removal system, the SENTINEL System, for clinical trials in the United States. The SENTINEL System uses a venous catheter to detect and aspirate contrast-laden blood before it enters the general circulation. A commercially-available cell salvage system can be used to minimize the amount of blood lost due to the aspiration process. This SBIR project is aimed at developing a supporting subsystem, the Contrast Extraction Monitor (CEM), for the SENTINEL System that instantaneously monitors and reports the amount of contrast being removed from the patient by the SENTINEL System. The CEM is pivotal to cost-effectively testing the SENTINEL catheter system in humans, as it would provide a direct measure of efficacy that would not otherwise be available. When approved for clinical use, the CEM will provide real-time feedback to the cardiologist that can be used to: (1) confirm that the SENTINEL aspiration system is functioning, (2) contour the treatment protocol relative to the risk of CIN, and (3) provide contrast exposure data for post- procedure case management. PUBLIC HEALTH RELEVANCE: Visualization of the blood vessels for life saving minimally invasive catheterization procedures requires the use of radiopaque contrast agents that are toxic to the kidneys. The Contrast Extraction Monitor, which is the focus of this SBIR application, will support the clinical testing of a device for removing contrast-laden blood from the patient before the contrast agent can reach the kidneys. After the Contrast Extraction Monitor is approved for clinical use, it will provide essential information about the amount of contrast removed from the patient, which is pivotal to a successful outcome.